Hepatic extraction of insulin and glucagon will be measured in anesthetized dogs by obtaining samples from the femoral artery, portal vein and hepatic vein. Blood flows will be measured in the hepatic artery and portal vein. The effect of alteration of portal vein insulin and glucagon concentrations by a variety of procedures on hepatic extraction of the two hormones will be determined. Effects of these various manipulations on hepatic carbohydrate metabolism will also be investigated. Recently material cross-reacting with antibody thought to be specific for pancreatic glucagon has been found in plasma of pancreatectomized dogs. The characteristics, biologic activity and origin on this material will be studied.